Antimalarial drugs. 24. Folate antagonists. 2. 2,4-Diamino-6-{[aralkyl and (heterocyclic)methyl]amino}quinazolines, a novel class of antimetabolites of interest in drug-resistant malaria and Chagas' disease

Abstract

Elslager, et at. methanol Hydrochloride (23). Bromomethyl 2,6-bis(3,4-dichlorophenyl)-4-pyridyl ketone (lie) (2 g) was suspended in EtOH (40 ml).NaBH4 (250 mg) was added, and the mixt was stirred for 1 hr at room temp. HC1 (3 N) was added to decompose excess NaBH", and the mixt was neutralized with Na2C03. Water (50 ml) was added, and the mixt was filtered. The solid was washed with H20 (x 2, 20 ml) and dried in vacuo. There was obtained 1.6 g (95%) of crude epoxide, mp 138-145°, containing ca. 5% of an unknown by tic. The epoxide (1.5 g) and (n-C4H,)2NH (5 ml) in EtOH (25 ml) were heated at reflux for 3 hr (complete by tic). Solvent and excess amine were removed in vacuo. The residual oil in Et20-z-Pr0H was treated with a satd soln of HC1 in z-PrOH. The ppt was washed with Et20 (x 3, 20 ml). Recrystn from EtOH afforded 1.5 g (71%) of 23, mp 220-222°. The above procedure is typical of the prepn of the 4pyridinemethanols described in Table III.Derivatives. The V-oxides 4a and 23a were prepd by treating the parent compds 4 and 23, respectively (as the free bases), in Et20 with 40% Ac02H in AcOH. The mixt was stirred 2 hr at 25°. For 4a, the soln was washed with 20% NaOH (x 2) and water (x 2), and dried (Na2S04). The solvent was removed, and the residue was dissolved in Et20. Et20-HCl was added, and the ppt was recrystd (EtOH) to give 4a (HC1 salt), mp 172-174°. In the case of 23a, the crude product pptd from the Et20 reaction mixt as the AcOH salt. This ppt was slurried in MeOH and treated with a little coned HC1. Water was added to the soln to ppt 23a (HC1 salt), mp [174][175].The O-succinoyl derivative 4b was prepd by heating parent compd 4 (free base) and succinic anhydride in Me2CO for 1 hr. The solvent was removed. The residue was dissolved in Et20 and treated with dry HC1. The mixt was stirred at 25°with an equal vol of H20 for 1 hr. Filtration gave crude 4b, mp 149-153°(HC1 salt), recrystd from CH3CN.The zV-succinoyl derivative 3a was prepd from parent compd 3 (free base) by treating an Me2CO soln with succinic anhydride at 25°for 1 hr. The solvent was removed and recrystn from C6H6 gave 3a, mp 104-107°. Folate Antagonists. 2.2,4-Diamino-6-[ [aralkyl and (heterocyclic)methyl]amino}quinazolines, a Novel Class of Antimetabolites of Interest in Drug-Resistant Malaria and Chagas' Disease"*"' *

Malaria Chemotherapeutics Part I: History of Antimalarial Drug Development, Currently Used Therapeutics, and Drugs in Clinical Development

“…Furthermore, this compound showed strong synergy with dapsone (55). [273] Pyrroloquinazolidinediamine derivatives were prepared in the early 1970s as folate antagonists and were found to display high antimalarial activity, [274,275] although pronounced toxicity prevented further development. Recently, the tetraacetyl prodrug 71 showed markedly superior efficacy and safety in a mouse model of severe malaria relative to artesunate (42).…”

New Potential Antimalarial Agents: Therapeutic-Index Evaluation of Pyrroloquinazolinediamine and Its Prodrugs in a Rat Model of Severe Malaria

“…PQD and derivatives of it are very active antimalarial agents in vivo and in vitro (6,12,16,21). Some derivatives were the most potent antimalarials discovered at the Walter Reed Army Institute of Research (WRAIR), with 50% inhibitory concentrations Ͻ0.01 ng/ml and excellent activity against Plasmodium falciparum strains resistant to pyrimethamine (unpublished data).…”

Antileishmanial activities of 2,4-diaminoquinazoline putative dihydrofolate reductase inhibitors

“…The inactivity of this compound and of compound 5, both of which contain a secondary aromatic amine, indicates that in this series a tertiary rather than secondary aromatic amine is required for antileishmanial activity. The relative inactivity of compounds 6 Although the primary purpose of these studies was to determine a structure-activity relationship, we were also interested in the biochemical basis of antileishmanial activity and for this purpose utilized our standard preparation of sonicated L. mexicana promastigotes. Antiamastigote activity of these 2,4-diaminoaquinazoline analogs of dihydrofolate was not well correlated with inhibitory activity against L. mexicana promastigote DHFR.…”